Vitamin E Supplementation Increases the Attractiveness of Males' Scent for Female European Green Lizards

Behavioural Ecology Group, Department of Systematic Zoology and Ecology, Eötvös Loránd University, Budapest, Hungary.
PLoS ONE (Impact Factor: 3.23). 04/2011; 6(4):e19410. DOI: 10.1371/journal.pone.0019410
Source: PubMed


In spite that chemoreception is important in sexual selection for many animals, such as reptiles, the mechanisms that confer reliability to chemical signals are relatively unknown. European green lizards (Lacerta viridis) have substantial amounts of α-tocopherol ( = vitamin E) in their femoral secretions. Because vitamin E is metabolically important and can only be attained from the diet, its secretion is assumed to be costly. However, its role in intraspecific communication is unknown.
Here, we experimentally show that male European green lizards that received a dietary supplement of vitamin E increased proportions of vitamin E in their femoral secretions. Furthermore, our experiments revealed that females preferred to use areas scent marked by males with experimentally increased vitamin E levels in their secretions. Finally, female preferences were stronger when vitamin E differences between a pair of males' secretions were larger.
Our results demonstrate that female green lizards are able to discriminate between males based on the vitamin E content of the males' femoral secretions. We suggest that the possible cost of allocating vitamin E to secretions, which might be dependent on male quality, may be a mechanism that confers reliability to scent marks of green lizards and allows their evolution as sexual signals.

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    • "Diet supplementation of α-tocopherol (= vitamin E) results in increased proportions of vitamin E in femoral gland secretions of male green lizards, Lacerta viridis and L. shreiberi (Kopena et al., 2011, 2014). This relationship between diet and secretions is important because vitamin E is the main compound in secretions of green lizards (Kopena et al., 2009; López and Martín, 2006), and females seem to prefer areas scent-marked by males with large proportions of vitamin E in secretions (Kopena et al., 2011), suggesting that this compound may function as a chemosignal probably indicating the quality of the male (i.e. the ability to obtain or select food of high quality) or his territory (i.e. the availability of high quality food within it). Within the organism, vitamin E is the main lipophilic antioxidant and radical scavenger involved in membrane defense and immuno stimulatory activity (Brigelius-Flohe and Traber, 1999). "
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    ABSTRACT: Many lizards have diverse glands that produce chemosignals used in intraspecific communication and that can have reproductive consequences. For example, information in chemosignals of male lizards can be used in intrasexual competition to identify and assess the fighting potential or dominance status of rival males either indirectly through territorial scent-marks or during agonistic encounters. Moreover, females of several lizard species "prefer" to establish or spend more time on areas scent marked by males with compounds signaling a better health or body condition or a higher genetic compatibility, which can have consequences for their mating success and inter-sexual selection processes. We review here recent studies that suggest that the information content of chemosignals of lizards may be reliable because several physiological and endocrine processes would regulate the proportions of chemical compounds available for gland secretions. Because chemosignals are produced by the organism or come from the diet, they should reflect physiological changes, such as different hormonal levels (e.g. testosterone or corticosterone) or different health states (e.g. parasitic infections, immune response), and reflect the quality of the diet of an individual. More importantly, some compounds that may function as chemosignals also have other important functions in the organism (e.g. as antioxidants or regulating the immune system), so there could be trade-offs between allocating these compounds to attending physiological needs or to produce costly sexual "chemical ornaments". All these factors may contribute to maintain chemosignals as condition-dependent sexual signals, which can inform conspecifics on the characteristics and state of the sender and allow to make behavioral decisions with reproductive consequences. To understand the evolution of chemical secretions of lizards as sexual signals and their relevance in reproduction, future studies should examine what information the signals are carrying, the physiological processes that can maintain the reliability of the message and how diverse behavioral responses to chemosignals may influence reproductive success.
    Hormones and Behavior 02/2015; 68(1):14-24. DOI:10.1016/j.yhbeh.2014.06.009 · 4.63 Impact Factor
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    • "In many lizard species, males exude femoral pore secretions. The compounds present within these secretions may provide information on aspects of male quality, such as immunocompetence [27] and health [30]. In addition, females may also be capable of discriminating among male color morphs by femoral pore secretions alone [31]. "
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    ABSTRACT: Non-random female mating preferences may contribute to the maintenance of phenotypic variation in color polymorphic species. However, the effect of female preference depends on the types of male traits used as signals by receptive females. If preference signals derive from discrete male traits (i.e., morph-specific), female preferences may rapidly fix to a morph. However, female preference signals may also include condition-dependent male traits. In this scenario, female preference may differ depending on the social context (i.e., male morph availability). Male tree lizards (Urosaurus ornatus) exhibit a dewlap color polymorphism that covaries with mating behavior. Blue morph males are aggressive and defend territories, yellow males are less aggressive and defend smaller territories, and orange males are typically nomadic. Female U. ornatus are also polymorphic in dewlap color, but the covariation between dewlap color and female behavior is unknown. We performed an experiment to determine how female mate choice depends on the visual and chemical signals produced by males. We also tested whether female morphs differ in their preferences for these signals. Female preferences involved both male dewlap color and size of the ventral color patch. However, the female morphs responded to these signals differently and depended on the choice between the types of male morphs. Our experiment revealed that females may be capable of distinguishing among the male morphs using chemical signals alone. Yellow females exhibit preferences based on both chemical and visual signals, which may be a strategy to avoid ultra-dominant males. In contrast, orange females may prefer dominant males. We conclude that female U. ornatus morphs differ in mating behavior. Our findings also provide evidence for a chemical polymorphism among male lizards in femoral pore secretions.
    PLoS ONE 07/2014; 9(7):e101515. DOI:10.1371/journal.pone.0101515 · 3.23 Impact Factor
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    • "The few studies on vertebrates that have examined signals of resource quality have also frequently focused on food availability. For example, male lizards artificially supplemented with dietary vitamins have correspondingly higher levels of the same vitamins in their femoral secretions, which females may use in mate choice (Martín and López 2006b; Kopena et al. 2011). However, food is rarely a limiting resource in mainland lizard populations, where feeding rates, particularly in temperate species, often equal laboratory ad libitum levels (Avery 1971, 1978; Edsman 1990), making the relative importance of dietary-derived olfactory cues questionable in the natural context of mate choice within this group. "
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    ABSTRACT: Signals used in female choice should honestly ad-vertise the benefits that males can provide, with direct benefits often argued as being more important than indirect benefits. However, the nature of direct benefits in species without paternal care or nuptial gifts is poorly understood. Previous studies on lizards suggest that females decide where to settle and assumedly who to mate with based on information contained in scent marks from territorial males. Access to high-quality thermal resources is crucial for female reproduc-tive success. Females may therefore be able to detect and exploit thermal-induced variation in the chemical composition of male scent marks when assessing the quality of his territory. We show that the amount of time male wall lizards (Podarcis muralis) are allowed to bask significantly alters the chemical composition of their femoral secretions used in scent marking. The direction of the change is consistent with adaptive plas-ticity to maintain signalling efficacy under warm conditions that increase evaporation of femoral secretions. The com-pounds affected by basking experience included those previ-ously associated with male quality or shown to mediate male– male competition in lizards. However, whilst female lizards could discriminate between scent marks of males that had experienced different basking conditions, they did not prefer-entially associate with the scent from males from high-quality thermal conditions. These results highlight the potential im-portance of a previously neglected environmental effect on chemical signalling. We suggest thermal effects may have significant consequences for scent-mark composition in vari-able environments, with potential repercussions on olfactory communication in lizards.
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